“If you choose to 'Download and Import' rather than just 'Download' it will place a copy in your project folder. Otherwise, the files are not tied to any particular project, so they are placed int he shared data folder on your local machine”.

After installation, Unity shows the snag screen “Unity v2.x. This version of Unity requires authorisation for use of it. Please press the 'Register' button to begin the authorization process. A one time 30-days free trial is available for everyone</del>”.

Indeed, free operation of Unity is offered by registration anyhow ( ”[x] Activate the free version of Unity” ).

Unreal Engine for Win7 and MacOSX - “Now FREE. FREE for game development. FREE for Virtual Reality. FREE for education. FREE for architecture. FREE for film. Pay a 5% royalty on games and applications you release. We succeed when you succeed”.

Unreal Engine is dedicated for more advanced users, though you may generate simple games by a graphical script language “Blueprints Visual Scripting”, creating an “AI Node Blueprint” without any C/C++ coding. Just real complex action and games need to be coded in C/C++.